Input devices, including proximity sensor devices (e.g., touchpads or touch sensor devices), are widely used in a variety of electronic systems. A proximity sensor device may include a sensing region, often demarked by a surface, in which the proximity sensor device determines the presence, location and/or motion of one or more input objects. Proximity sensor devices may be used to provide interfaces for the electronic system. For example, proximity sensor devices may be used as input devices for larger computing systems (e.g., opaque touchpads integrated in, or peripheral to, notebook or desktop computers). Proximity sensor devices are also often used in smaller computing systems (e.g., touch screens integrated in cellular phones).
Some proximity sensor devices may also detect force on the surface of the input device. The surface of the input device may have a non-uniform bending response to the same amount of force on different parts of the input surface. Thus, accurate detection of force may include accounting for the non-uniform bending response of the input surface.